There are an increasing number of protein drugs in the pipeline, whose cost of production is very high compared to synthetic, small molecule drugs. Further, a number of protein drugs are coming off patent in the next few years, which will create an opening for a market for generic version of these drugs, if they can be produced at significantly lower cost and demonstrate bioequivalence. The Phase I results clearly indicated that a powerful and commercially important application of the deltaPhase System is in the recombinant production of proteins, some of which are difficult to express at high levels as soluble proteins. Motivated by the increasing importance of recombinant protein drugs, and the clear need for low-cost expression and easy purification of proteins, the goal of the Phase II research will be to advance the technology for the expression and purification of recombinant proteins that will be eligible for biogenerics within the next three years, with high expression and at high purity levels. The enabling technology that will allow Phase Bioscience to achieve this objective is the deltaPhaseTM System, a novel platform technology for high-level expression and simple, non-chromatographic purification using a class of polypeptide tags, termed elastin-like polypeptides (ELPs). The fundamental basis of this technology is the discovery that proteins and peptides fused to an ELP retain the environmentally triggered (temperature, salt) soluble-insoluble phase transition behavior of ELPs, and that this reversible phase transition can be carried out in cell lysate to separate ELP fusions from other cellular proteins to homogeneity by a few phase transition cycles. The impact of the technology will be to provide the protein industry with the ability to produce proteins, especially biogeneric proteins, at significantly lower cost by removing chromatography from the purification process. This will make these drugs more competitive with small molecule drugs, and reduce the cost of drugs to patients. The Specific Aims of the project include: 1. Express six pharmaceutically-relevant, biogeneric candidate recombinant fusion proteins in E. coli and CHO; 2. Purify the proteins to at least 90% purity, as measured by LC-MS; and 3. Demonstrate their bioactivity compared to the commercially produced proteins. [unreadable] [unreadable] [unreadable]